Josiah s



(No Model.)

J. S. TYREE. LITMUS PENCIL.'

N0. 458,244. Patented Aug. 25, 1891.

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investigated, great difficulty is at present exsists in preparing the reagent in solid condition, giving it an elongated form, and inelos- .away portions of the wood at the end the re- UNITED STATES ATENT Fries..

JOSIAH S. TYREE, '3F WASHINGTON, DISTRICT OF COLUMBIA.

L lTlVlUS PENCIL.

Application filed January 23, 1891.

.To all whom it Wray concern:

Beitknown that I, JosrAH S. TYREE, a citizen of the United States, residing at Vashington, in the District of Columbia, have invented certain new and useful Improvements in Litmus Pencils; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.`

This invention relates to reagents.

The object of the invention is to keep a reagent in such form that it will always be pure and unchanged, and will thus ever be i y1 condition correctly and accurately to make manifest the known effect of the particular reagent, and to be able readily to present the reagent just as required for use in its pure and unchanged form.

lVith this object in view theinvention coning it between grooved pieces of wood or placing it in a piece of wood perforated lengthwise, the whole having the appearance of the ordinary lead-pencil, whereby upon cutting agent will always be presented in condition fresh for use.

The invention consists, particularly, in litmus combined with clay and gum in suitable proportions and confined in an envelope of wood or thelike, readily removable, and which vwill protect the compound from airand light.

One form of embodiment of the invention is illustrated in the accompanying drawings, in which.-

Figure 1 is a perspective View of the pencil, and Fig. 2 is alongitudinal sectional view thereof. In these drawings, Arepresents the litmus combined with the clay and gum, and B represents the cover or envelope. This cover or envelope is preferably of wood, though, if desired,it maybe of any othersuitable substance, such as paper.

In the making of delicate tests to ascertain acid or alkaline condition of some substance perienced, with uncertainty and error of result, from the condition in which many of the reagents, even where carefully kept, are found. Thus in employing litmus this sub- Serial No. 378,777. (No model.)

stance, as usually presented and obtained by the chemist for work, is generally already in paper, the paper being saturated with a solution thereof. The paper thus saturated with the solution is commonl)v known as test-paper 5 but as a matter of fact the paper thus charged with litmus is itself often either acid or alkaline, resulting from conditions of its manufacture, so that the name test-paper is often erroneous, the employment of the substance frequently leading to diametrcally unjust conclusions. Owing to the spare solubility of litmus in water, it is impossible to prepare a solution of sufiieient density to impregnate paper and such mediums with a sufficient quantity of litmus or the like to procure a` reaction indicating in all cases the presence of either acids or alkalies. Furthermore, deposit from solutions upon paper or the like is generally irregular, so that there will be more litmus or other test-agent taken from the solution upon one part than upon another. The exceeding sensitiveness of testpaper to light, to air, and to other oxidizing iniiuen ces renders them often totally unfit for use in a very short time. `Finally, the employment of test-papers and solutions is not always convenient.

By my invention it is intended to obviate.

all difficulties above set forth, and to be able at all times to present the testing-agent in its native, original, or real condition, at the same time to be able to have it in form which may always be readily at hand, and to present it with facility and convenience.

As an example, l. will show how litmus may be employed with my invention. l take ordinary litmus and incorporate with it fine clay and some suitable gum-such as pure gumarabic-theparts being combined in about the proportions of seventy-iive percent. of litmus, fifteen per cent. of clay, and ten per cent. of gum. of gl ycerine for the purpose of preventing the compound from becoming dry. After theingredients are thoroughly mixed portions are then taken and rolled out into thin cylinders and placed between two or more grooved pieces of wood so as to form a holder correspending to the wooden portion of the ordinary lead-pencil. The pieces are then suitably made to adhere. lt will be obvious that the To this may be added a small quantity essaie us will thus be protected from influences ing to lessen its purity and its certainty ise. l employ the litmus it will only beneeesto shave off one end of the wood and to 'she portion of the litmus thus exposed i a suitable backing surface-such as r-the substances with which it is coml tending' to facilitate this marking, which d not be possible with the litmus in the state. It is preferable to coat the paper ly and uniformly. The papel` being coated, if the test is to be made immediit is not material that it should be neuaven if the paper be acid or if it be pro- :edly alkaline in substance, as the test )e made immediately the acid or alkali i paper will not have time to injure the s, and its appearance immediately after st will give a correct indication. ny pencil the litmus or other test-agent ipletely protected from all oxidizing' ines, and the great advantage is presented ays having fresh reagent at hand Withlving to go through the inconvenience ping through a dark closet or going to -tight receptacle for the same. pencil, like a lead-pencil, may be carried pocket or in a memorandum-book, and mus or other test agent is always im- :ely at hand in its purest condition for id being applied, as aforesaid, by simoking the end of the pencil the rf; tgent properly exposed up` i. a suitable backlhe reagent is thus also ever presented most concentrated form, so that the st quantities of acid or alkali can at a detected. As the pencil is stroked he backing, even if the outside .of the i portion had become oxidized, this d portion would be within and a fresh ized portion would co vcr it. IVith, my physicians and others who should frequent tests may always have the ready at hand. Ve and the same pencil I may have two rs of litmus,

one prepared to test for acid and the other prepared to test for alkali, or the same pencil may contain two different reagents. The ends will then be suitably marked. For a continuous test, where several reagents have to be used in sequence, the pencil may contain them all.

From the foregoing it will be my new presentation of litmus a test agent in a form not too concentrated is provided, that by reason of the combination with the substances mentioned marking on a suitable surface is facilitated, and that complete protection from the hands and light is afforded.

As a substitute for the clay, any gum, paraffine, and wax may under some circumstances be used.

Having thus fully what I claim as new, Letters Patent, is-

l. An implement for chemical tests, consisting of litmus combined with clay and gum in about the proportions specified, thc compound being inclosed in an envelope of Wood or the like, substantially as described.

2. An implement for chemical tests, consisting of litmus combined with clay and gum in about the proportions of seventy-five per cent. of litmus, fifteen per cent. of clay, and ten per cent. of gum, the compound being inclosed in an envelope of wood or the like, substantially as described.

3. An implement for chemical tests, consisting` of litmus combined with clay and gum in about the proportions of seventy-tive per cent. of litmus, iifteen per cent. of clay, and ten per cent. of gum, to which compound is addetta small quantity of glycerine, the whole being confined in an envelope of Wood or the like, whereby protection from air and light is afforded, substantially as described.

seen that by described my invention, and desire to secure by In testimony whereof I aiiix my signature in I presence of two witnesses.

. JosIAn s. TYREE. Witnesses:

DAVID II. MEAD, G. Il. KEEFER. 

